石竹叶面积指数的测定

通过对石竹叶面积指数测定表明 ,叶面积随胸径的增大而趋于增大 ,当林分密度为 30 0 0 0～ 375 0 0株·hm-2 ,平均直径 2～ 3cm时 ,叶面积指数趋于合理 ,这时产量也最高     

Conducting surveys on forestry attitudes and practices in Leyte communities,Philippines: Experiences and lessons learnt

A survey of forestry practices and attitudes was undertaken in four communities in Leyte, the Philippines, to improve understanding of the social and economic factors affecting small-scale forestry development. The survey had three main data collection activities — initial focus group discussions (FGDs), household interviews, and reporting and validation FGDs. A team of enumerators was selected for household interviews which consisted of both males and females, to avoid potential problems of unwillingness of people to talk with those of the opposite gender. The interviewers were also required to be able to speak local dialects (Cebuano and Waray Waray), the survey questionnaires being administered in these dialects. Various methods were used to gain the support and assistance of local government units and barangay captains. Some difficulty was experienced by the survey team in the first community due to barangay elections at the time of the survey, and the requirement by the University of Queensland Ethics Committee that respondents sign a consent form. This requirement was found to be not culturally appropriate for the Leyte smallholder communities. Offering goods at the end of the interview was found to be of limited value for encouraging participation in the survey. Provision of food and drinks were found to encourage FGD participants to express their views, but too much alcohol had a negative effect. The importance of providing comprehensive feedback to respondents and involving them and other stakeholders in development of policy recommendations was apparent. These survey experiences provide valuable insights which are not generally available in textbooks on sample surveys, and provide lessons for planning and conducting smallholder community survey into natural resource management issues.     

Generalized height–diameter models—an application for major tree species in complex stands of interior British Columbia

Using permanent sample-plot data, selected tree height and diameter functions were evaluated for their predictive abilities for major tree species in complex (multiple age, size and species cohort) stands of interior British Columbia (BC), Canada. Two sets of models were evaluated. The first set included five models for estimating height as a function of individual tree diameter, the second set also included five models for estimating height as a function of individual tree diameter and other stand-level attributes. The inclusion of the BAL index (which simultaneously indicates the relative position of a tree and stand density) into the base height–diameter models increased the accuracy of prediction for all species. On average, by including stand level attributes, root mean square values were reduced by 30.0 cm. Based on the residual plots and fit statistics, these models can be recommended for estimating tree heights for major tree species in complex stands of interior BC. The model coefficients are documented for future use.     

Plantation future of bamboo in China

In the past, utilization of bamboo resources in China has been traditionally dominated by direct consumption of local farmers as minor forest products with weak linkage with market. In recent years, the over-supply of grains and rapid degradation of agricultural environment call for alternative crops that can be developed through integrating the environmental plantation with the market demands. Closely associated with forestry and agriculture, bamboo is able to deal with the new challenges which China‘s agriculture is facing. Of 534 documented bamboo species in China, 153 species produce edibleshoots and of which 56 species are recommended for agricultural plantation; 139 species provide timbers and of which 58 species recommended; 116 species can be splited as good strips for weaving and of which 22 species recommended; 88 species are considered as garden bamboos and of which 34 species recommended; 45 species are able to produce paper pulp and of which 18 species recommended.     

浅论北方地区园林绿化设计中的节水措施

针对我国北方城市园林绿化设计中存在的用水不合理问题,阐述了发展节水型园林的必要性,提出了北方城市园林绿化设计中的节水措施。     

Economic Benefit Analysis of Sedimentation Reduction by Forests in Miyun Watershed, Beijing

Soil erosion causes the loss of the fertilized surface soil. The eroded soil can be transported into rivers, lakes and reservoirs. The sedimentation raises the riverbed. It also reduces the flood discharge ability of rivers and the storage ability of reservoirs(Sun Lida, et al, 1995; Yu Zhimin, et al, 1999). Various researches proved that forests could reduce soil erosion. Forests in the watershed can decrease the sedimentation of the reservoir (Guo Zhongwei, et al, 1998; Qing Yongsheng, 2…     

入世条件下林业可持续发展问题的探讨

世界贸易组织(简称WTO)，作为处理世界自由贸易机制的国际组织，允许为可持续发展和保护自由贸易和环境选择利用世界自然资源。中国作为世界贸易组织成员国，签定入世议定书，入世后中国在林业的可持续发展方面受到世界贸易组织的条约和原则的制约和挑战。中国的林业资源应当作为基础资源加以保护，政府的行政管理职能在世界贸易组织的原则下加以改革。因此，中国林业的可持续发展的目．标是优先处理环境保护和经济发展的关系。在入世条件下，按照世界惯例，中国林业资源可持续发展问题瞄准中国林业体制改革，以便适用中国天然林业战略，依靠科技进步依法保护中国环境，特别是在中国林业保护和处理环境和自然资源等关系方面。依据世界贸易组织的协议和规则，建立林业的生态化体系，尤其是GATT20条的规定，保护中国林业可持续发展，为中国林业创建国际环境。表1参21。     

第二代杉木林养分动态研究

根据连续定位观测所取得的数据,对4个小集水区第二代10年生杉木人工林生态系统中的养分循环进行了研究.结果表明.集水区由降水输入的N、P、K、Ca、Mg等营养元素总计为59.285kg/hm2a,径流输出为38.938kg/hm2a,净积累量为20.347kg/hm2a.与该林分7年生时相比,净积累量提高了7.2%,说明集水区第二代杉木林生态恢复处于进展的变化过程.     

对住宅建设的一点看法

本文着重从几个方面论述住宅建设今后的发展方向。使住宅总体规划合理,经济适用,住宅建设与环境协调,达到可持续发展原则的绿色住宅和生态住宅区。     

要统筹解决西北和华北地区干旱缺水问题

针对某些学者“西北不缺水” ,南水北调主要解决华北地区水资源短缺的观点 ,分析了我国水资源与人口、耕地、矿产资源分布的不协调 ,气候变暖将使北方干旱持续到 2 0 15年 ,西北地区比华北地区更干旱缺水 ,西部生态环境建设和开发亟需调水 ,提出南水北调是合理配置水资源、保持社会稳定的需要 ,大西线调水是统筹解决北方干旱缺水的必由之路 ,并提出西南地区水电开发应与大西线调水同步进行